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Bug fix for PR1279. When isDead is propagate by copy coalescing, we keep length 

of dead def live interval at 1 to avoid multiple def's targeting the same
register. The previous patch missed a case where the source operand is live-in.
In that case, remove the whole interval.

llvm-svn: 35512
This commit is contained in:
Evan Cheng 2007-03-30 20:18:35 +00:00
parent 9ca63d605c
commit 48dd5e7d44
1 changed files with 10 additions and 5 deletions
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15
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -915,6 +915,7 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI,
// Check if it is necessary to propagate "isDead" property before intervals
// are joined.
MachineBasicBlock *CopyBB = CopyMI->getParent();
MachineOperand *mopd = CopyMI->findRegisterDefOperand(DstReg);
bool isDead = mopd->isDead();
bool isShorten = false;
@ -941,9 +942,15 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI,
isShorten = true;
RemoveStart = getDefIndex(getInstructionIndex(LastUse));
RemoveEnd = SrcEnd;
} else if (RemoveStart > 0)
// A dead def should have a single cycle interval.
++RemoveStart;
} else {
MachineInstr *SrcMI = getInstructionFromIndex(SrcStart);
if (SrcMI) {
MachineOperand *mops = SrcMI->findRegisterDefOperand(SrcReg);
if (mops)
// A dead def should have a single cycle interval.
++RemoveStart;
}
}
}
}
@ -959,7 +966,6 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI,
LiveVariables::VarInfo& dvi = lv_->getVarInfo(repDstReg);
// Is the value used in the current BB or any immediate successroe BB?
MachineBasicBlock *CopyBB = CopyMI->getParent();
if (dvi.UsedBlocks[CopyBB->getNumber()])
goto TryJoin;
for (MachineBasicBlock::succ_iterator SI = CopyBB->succ_begin(),
@ -1018,7 +1024,6 @@ TryJoin:
if (SrcMI) {
MachineOperand *mops = SrcMI->findRegisterDefOperand(SrcReg);
if (mops)
// FIXME: mops == NULL means SrcMI defines a subregister?
mops->setIsDead();
}
}